Digital printing systems typically employ a dot placement pattern where circular dots are placed on a rectangular coordinated (Cartesian) grid. This pattern is convenient for the calculation of the placement of data and allows good generation of vertical and horizontal lines. However, the circular dots have to be relatively large to completely cover corresponding rectangular areas of the print media. A relatively large amount of overlapping of deposited ink occurs in areas directly between two adjacent dots, and a small amount of overlapping of deposited ink occurs at points on the grid that fall between diagonal dots. As such, rectangular systems using larger drops require more ink or toner to completely cover the print media and are not efficient for some printing applications.
One way to reduce the amount of ink overlap is to print on a hexagonal grid pattern. Hexagonal grid patterns inherently have an efficient geometry to allow circles to be closely packed when filling in an area on the print media, thus requiring less ink.
A system using a hexagonal grid will cover a higher percentage of the paper with a single drop, reducing the amount of ink required to cover a page. However, while hexagonal grid patterns produce high quality images, they are not optimal for other printing applications such as text and line graphics.
The present invention includes as one embodiment a method for printing ink on a print media with a fluid ejection device of an inkjet printing mechanism, comprising generating first grid pattern data and second grid pattern data different from the first grid pattern data, sending the first grid pattern data to a first printing mechanism of the fluid ejection device and sending the second grid pattern data to a second printing mechanism of the fluid ejection device.